President Joe Biden once hoped his trip to Asia this week would strengthen American alliances, counter China's influence and prove to Americans he's got the stamina for another term in office.

But the trip he planned didn't materialize. The standoff over raising the US debt ceiling, which could lead to a first-ever default if not resolved before next month, is proving more pressing.

While Biden is leaving Washington on Wednesday for Japan, he's skipping the pre-planned second half of his trip, which included a stop in Australia and Papua New Guinea.

White House press secretary Karine Jean-Pierre said Tuesday in a statement that the US president spoke to Australian Prime Minister Anthony Albanese to inform him he will be "postponing" the trip and invited the prime minister for an official state visit "at a time to be agreed by the teams." Albanese said later that a summit of the Quad leaders in Sydney next week had been canceled after Biden pulled out of the visit, but that talks could still proceed as leaders visit Japan. Jean-Pierre added that the "President's team engaged" with the prime minister of Papua New Guinea.

The political stalemate over the borrowing limit doesn't quite match the image of functional democracy Biden has sought to present to the world as he works to restore faith in America and counter the rise of authoritarian regimes.

A default on US obligations would further shake an already-unsteady global economy and, according to Biden's aides, cause irreparable reputational damage. Just the political wrangling has caused market turmoil. It's almost certain to arise in Biden's discussions with fellow leaders in Japan, which is hosting this year's Group of Seven talks in Hiroshima.

The prospect of a US-led global economic meltdown is not exactly what Biden and his team had in mind as they were preparing for this year's summit, which comes at a critical moment for the war in Ukraine and amid growing tensions with China.

Because Japan, the only Asian member of the G7, is hosting this year's summit, China is expected to loom larger than usual. Biden's other stops in the South Pacific and Australia were similarly meant to demonstrate American commitment to a region where Beijing's provocative actions are causing growing concern.

Senior US administration officials said Biden's goal is to emerge from the summit demonstrating a shared approach to China among the group's members, who haven't always appeared aligned in the past.

Comments from French President Emmanuel Macron this spring cautioning Europe against getting drawn into a US-China conflict over Taiwan only underscored the differing views.

Heading into this week's summit, American officials voiced confidence there would be unity on display, particularly when it comes to condemning China's coercive economic practices, even as they acknowledged individual countries would make their own decisions.

The symbolism of holding this year's G7 summit in the riverside city of Hiroshima is hard to miss. The city was leveled in 1945 when the United States dropped the world's first atomic bomb, killing more than 100,000 people and accelerating an end to World War II.

As world leaders gather in the rebuilt city center, nuclear threats persist -- in the region from North Korea; in Iran, which is accelerating its nuclear program; and from Russia, whose nuclear saber-rattling has lent the war in Ukraine a menacing undercurrent.

Since Russia invaded Ukraine, the G7 has acted as the leading body to enact sanctions on Moscow and drive toward providing Kyiv with ever-more-advanced weaponry. In many ways, the war has reinvigorated the bloc, which had struggled in recent years to coalesce around a unifying purpose. Biden's aides have taken to referring to the G7 as the "steering committee for the free world."

Even Japan has embraced the Ukraine cause, to the surprise of some in the West. Tokyo is in talks to open a NATO liaison office, the first of its kind in Asia, the country's foreign minister told CNN in an exclusive interview on last week, saying Russia's invasion of Ukraine has made the world less stable.

Fourteen months in, however, the invasion is still testing the alliance's ability to remain united, particularly without a clear path to ending the fighting. Western leaders hope an upcoming Ukrainian counteroffensive can help the country gain leverage in eventual negotiations with Russia -- though how, when and where those talks might occur remain undecided.

China has offered to play a role in the eventual peacemaking, an offer met with deep skepticism in Washington. European leaders have shown more willingness to entertain Beijing's offer. But a solution remains far off.

Each of the European members of the G7 -- Macron, Italian Prime Minister Giorgia Meloni, German Chancellor Olaf Scholz and British Prime Minister Rishi Sunak -- hosted Zelensky during a tour of the continent last week, pledging billions of dollars in new military aid.

The commitments, which included air defense missiles and attack drones, were a significant boost in military pledges and reflect a growing sense that Europe must assume a more central role in arming Ukraine. The United States remains the largest contributor of military assistance to Kyiv, but how long that support can be sustained remains an open question.

Biden's fellow leaders will have undoubtedly taken notice, with no small measure of alarm, at statements made last week by former President Donald Trump during a CNN town hall casting doubt on his support for Ukraine and pledging to resolve the crisis in a day.

Trump's potential return to the White House, or the election of another like-minded Republican, has worried Ukrainian and western leaders alike, according to diplomats and other officials. The impending GOP primary and the general election that will follow lends another layer of uncertainty to a western alliance that, so far, has remained remarkably united in its support for Zelensky and Ukraine.

As world leaders make their own assessments of Biden's political capital, the ongoing debt ceiling talks provide a timely backdrop at this week's summit.

"I assume President Biden will say he's working on it, and doing everything he can to avoid it, and it's sort of unthinkable that the US would default on its debts, and probably try to reassure them that that's not going to happen," said Matthew Goodman, senior vice president for economics at the Center for Strategic and International Studies in Washington. "Among G7 partners, there are already questions about what's going to happen in the 2024 election. And I'm sure that will be another theme hanging over the discussions."

White House officials insist there remains strong bipartisan support for Ukraine in Congress, and Republican leaders have said as much when asked. But Biden hasn't requested additional aid money since the GOP took control of the House of Representatives last year, and Trump's sway among conservatives in the chamber remains strong -- leaving open the possibility that future American support could come in far smaller than previous packages.

Biden, for now, remains at the forefront of global diplomatic efforts behind Ukraine. But as his own reelection effort heats up, some in Europe fear a combination of domestic distractions and a more isolationist Republican opponent will cause his ability to lead the coalition to wane.

Biden's advisers foresee a different scenario. They believe Biden's presence on the world stage can bolster his standing with voters, and see his foreign engagements as opportunity to demonstrate both his leadership and his endurance. An eight-day swing through Asia, grueling for any president, would have provided a counterpoint to accusations from his opponents that Biden is too old to be president.

That was before the trip got cut short.